A suicide bomber in an explosives-laden fuel tanker blew it up under a highway bridge near the town of Saqlawiya, about 10 km (six miles) north of Falluja, causing the bridge to collapse and destroying one of two army tanks parked on top, police said. Gunmen then attacked and destroyed the second tank.

Simultaneously, dozens of militants attacked a police station in Saqlawiya, forcing its occupants to surrender. Army helicopters later attacked the gunmen in the police station.

There was no immediate word on the casualty toll from those assaults, which occurred during a standoff between the army and al Qaeda-linked militants who overran Falluja two weeks ago.

Two years after U.S. troops left Iraq, violence has climbed back to its highest levels since the sectarian bloodshed of 2006-07, when tens of thousands of people were killed.